Theresa May revealed a new insurance deal at the summit in Hamburg that will help Africa when humanitarian disasters strikes and secure £60 million to help Africa integrate into global financial markets.
However, Mohamed Adow, Christian Aid's international climate lead, said the plan is "badly flawed because it makes no mention of climate change".
He said: "Africa is suffering climate impacts, not least economically, that it did not cause. Africa's poorest people are among the worst hit by impacts such as the horrendous famine across East Africa.
"Just a few weeks ago African leaders affirmed their support for growing their economies sustainably, and called on rich countries to make good on their promises of support and finance."
While Adow admitted the plan "looks like a generous offer", he said it won't truly help Africa unless it develops "clean jobs that the poorest can access". He added that future jobs and infrastructure adapting to climate change should have been at the heart of the UK's announcement.
Theresa May said the protection scheme will be a quicker, more reliable and cost-effective way of dealing with catastrophes like floods and droughts.
Around £30 million of UK aid funding will be used for the scheme over the next four years. Her idea is that boosting prosperity will help curb migration and stop people becoming radicalised by lifting millions out of poverty
A London Centre for Global Disaster Protection is being created that will bring together experts to increase disaster planning and create insurance to deal with the fallout when a crisis hits.
May said: "We must not forget that progress in Africa benefits the UK at home.
"Our international aid work is helping to build Britain's trading partners of the future, creating real alternatives to mass migration, and enhancing our security, while simultaneously ensuring we abide by our moral responsibility to meet the immediate humanitarian needs of some of the poorest people on earth."
However, Adow insists that this is not the only way Africa wants to bring about prosperity. He urged the UK and other G20 countries to support its Africa Renewable Energy Initiative.
He said: "African leaders have repeatedly stated that they want more than a climate risk insurance scheme.
"Just three weeks ago at the African Ministerial Conference on the Environment, they called for richer countries do more to cut their own carbon emissions and increase their support to the most vulnerable and worst affected communities and countries who are least able to protect themselves from climate change."